Longitudinal Associations Among Pain, Posttraumatic Stress Disorder Symptoms, and Stress Appraisals

Comorbidity of posttraumatic stress disorder (PTSD) and pain is well documented, but the mechanisms underlying their comorbidity are not well understood. Cross-lagged regression models were estimated with 3 waves of longitudinal data to examine the reciprocal associations between PTSD symptom severity, as measured by the Clinician-Administered PTSD Scale (CAPS; Blake et al., 1995), and pain, as measured by a brief self-report measure of pain called the PEG (pain intensity [P], interference with enjoyment of life [E], and interference with general activity [G]; Krebs et al., 2009). We evaluated stress appraisals as a mediator of these associations in a sample of low-income, underserved patients with PTSD (N = 355) at federally qualified health centers in a northeastern metropolitan area. Increases in PTSD symptom severity between baseline and 6-month and 6- and 12-month assessments were independently predicted by higher levels of pain (β = .14 for both lags) and appraisals of life stress as uncontrollable (β = .15 for both lags). Stress appraisals, however, did not mediate these associations, and PTSD symptom severity did not predict change in pain. Thus, the results did not support the role of stress appraisals as a mechanism underlying the associations between pain and PTSD.